JP4407950B2 - Noise reduction structure of concrete viaduct - Google Patents

Description

This invention relates to noise reduction structure for concrete viaduct to reduce the noise generated from the concrete viaduct.

  In the structure, vibration is excited as the train passes and solid sound is generated. Such solid sound is radiated into the structure immediately after generation, or radiated out of the structure after propagating in a part of the structure. It is clear that such structural noise is mainly caused by bending vibration of girder members such as main girders and vertical girders and tension plates in iron girders, and a large factor due to bending vibration of floor slabs in concrete viaducts. It is becoming. Conventionally, concrete viaducts have a higher weight than members of steel girders because the weight of the members is generally greater than that of iron girders and the rigidity is high, and the concrete material itself has some vibration damping capability. Was not a significant size.

  However, although concrete viaducts are smaller than iron girders, they still have causes of structural noise, and the problem of structural noise tends to become apparent as the speed of trains around the Shinkansen increases in recent years. It is in. With respect to noise generated on the bridge, such as rail / wheel noise and vehicle body aerodynamic noise, the noise level value can be reduced relative to the sound receiving point along the line by measures such as installing a soundproof wall on the structure. However, effective measures cannot be taken for the structure noise in the propagation path between the sound source and the sound receiving point, and the noise is directly propagated to the sound receiving point. As sound source power, although noise on the bridge such as rail-to-wheel noise is larger, noise at the receiving point along the rail line does not always contribute to the contribution of noise on the bridge, and structural noise cannot be neglected. There are many cases where contributions are made. In recent years, measures against bridge noise, such as raising the noise barrier, have been reinforced, but the measures for structural noise are lacking in decisiveness, and the problem of structural noise is being highlighted. Thus, in recent years, the need for countermeasures against structural noise has increased, and noise reduction measures for viaducts have been proposed. In a conventional viaduct noise reduction structure, a sound-insulating ceiling is arranged in parallel with the bottom surface of the floor slab at a distance from the bottom surface of the viaduct (see, for example, Patent Document 1). In such a conventional viaduct noise reduction structure, the noise of the structure radiated from the lower surface of the viaduct floor slab is blocked by a sound-insulating ceiling in which a vibration-proof rubber and a sound insulating plate are combined.

Japanese Patent Laid-Open No. 11-269993

  In the conventional viaduct noise reduction structure, there is a gap between the underpass floor slab bottom and the sound-insulating ceiling, so it is difficult to suppress the vibration of the bottom slab that causes structural noise. There was a problem that the soundproofing effect against the structure noise radiated from the underside of the plate was low. In addition, the conventional noise reduction structure of the viaduct is constructed under the viaduct or in places where roads pass along the road, and by absorbing or insulating the noise generated outside the viaduct, The main purpose is to prevent the noise from becoming a loud noise environment due to the structural noise. For this reason, even if such a sound insulation structure is disposed in close contact with the backside of the viaduct floor slab, it is not intended to reduce structure noise generated from the viaduct itself, so the structure of the viaduct It cannot be expected to be very effective in reducing noise. In addition, with steel girders, the weight and rigidity of the members are smaller than those of concrete viaducts, and the area of the girders themselves is small and the vibration damping capacity of iron is small. Easy. However, the concrete viaduct has a problem that it is difficult to take measures against noise because the weight and rigidity of the member are large and it is difficult to obtain a vibration reduction effect on the girder.

Object of the present invention is to provide a noise reducing structure of concrete viaduct which can reduce the construction noise from concrete viaduct.

The present invention solves the above-mentioned problems by the solving means described below.
In addition, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this embodiment.
The invention of claim 1, a noise reduction structure of concrete viaduct to reduce the noise generated from the concrete viaduct (E), damping layer damping vibrations of the lower surface of the concrete viaduct (E ₃₎ and (2) , comprising a constraining layer (3) and to restrain the vibration damping layer, said damping layer, the upper surface of the damping layer to a lower surface of said concrete viaduct are in close contact, the constraining layer stiffness than the low Young's modulus It is formed of vulcanized rubber of EPDM, which is a viscoelastic material of 10 to 100 MPa, and the constraining layer is an elastic material having rigidity higher than that of the vibration damping layer, and inorganic particles obtained by binding inorganic small particles with an epoxy resin. A concrete viaduct noise reduction structure (1), which is formed of a binder and absorbs noise from a sound source below the concrete viaduct toward the lower surface of the constraining layer .

A second aspect of the present invention, a noise reduction structure of concrete viaduct to reduce the noise generated from the concrete viaduct (E), damping layer damping vibrations of the lower surface of the concrete viaduct (E ₃₎ and (2) And a soundproof layer (7) for reducing the transmission of vibration from the vibration damping layer, and a constraining layer (3) for restraining the soundproof layer, the vibration damping layer being in close contact with the lower surface of the concrete viaduct, It is made of vulcanized rubber of EPDM, which is a viscoelastic material having a higher elastic modulus than that of the soundproof layer and a Young's modulus of 10 to 100 MPa, and the soundproof layer has a lower elastic modulus than that of the vibration damping layer and has a Young's modulus. It is formed of EPDM vulcanized rubber foam rubber, which is a viscoelastic material of 10 MPa or less, and the constraining layer is higher in rigidity than the vibration damping layer and the soundproof layer and has a Young's modulus of 3.0 × 10 ³ MPa or more. It is formed by a metal steel plate that is an elastic material This is a concrete viaduct noise reduction structure (1) characterized by the above.

According to a third aspect of the present invention, in the noise reduction structure of the concrete viaduct according to the second aspect , the sound absorbing layer is in close contact with the lower surface of the constraining layer and absorbs noise from the sound source below the concrete viaduct toward the lower surface of the viaduct. A concrete viaduct noise reduction structure characterized by comprising (8).

A fourth aspect of the present invention, a noise reduction structure of concrete viaduct to reduce the noise generated from the concrete viaduct (E), damping layer damping vibrations of the lower surface of the concrete viaduct (E ₃₎ and (2) And a soundproof layer (7) for reducing the transmission of vibration from the vibration damping layer, and a constraining layer (3) for restraining the soundproof layer, the vibration damping layer being in close contact with the lower surface of the concrete viaduct, It is made of vulcanized rubber of EPDM, which is a viscoelastic material having a higher elastic modulus than that of the soundproof layer and a Young's modulus of 10 to 100 MPa, and the soundproof layer has a lower elastic modulus than that of the vibration damping layer and has a Young's modulus. It is formed of EPDM vulcanized rubber foam rubber, which is a viscoelastic material of 10 MPa or less, and the constraining layer is an elastic material having higher rigidity than the vibration damping layer and the soundproof layer, and the inorganic small particles are made of epoxy. Resin-bound inorganic particle binder Thus it is formed a concrete viaduct noise reduction structure, characterized in that to absorb the noise toward the lower surface of the constraining layer from the sound source below the concrete viaduct (1).

  According to this invention, the structure noise from the viaduct can be reduced.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view schematically showing a viaduct provided with a noise reduction structure for the viaduct according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing a state cut along line II-II in FIG.
Vehicles V ₁ and V ₂ shown in FIGS. 1 and ₂ are moving bodies that travel along tracks R ₁ and R ₂ . The vehicles V ₁ and V ₂ are railway vehicles such as trains or trains, for example. The vehicle V ₁ travels on a track R ₁ on the viaduct E, and the vehicle V ₂ travels on a track R ₂ below the viaduct E. Tracks R ₁ and R ₂ are paths (tracks) on which the vehicles V ₁ and V ₂ travel. Trajectory R _1, R ₂ includes a rail R ₃ for running the vehicle V _1, V ₂ and supporting the wheels of the vehicle V _1, V ₂ guide, and the like slab plate R ₄ for supporting the rail R ₃ It is configured. The tracks R ₁ and R ₂ are, for example, slab tracks in which the road bed and sleepers are integrated.

Viaduct E is a subgrade for supporting a track R ₁ (base), a structure for continuously elevated trajectory R _1. The viaduct E is, for example, a structure in which a certain section of a railway is made into a bridge structure in order to make a three-dimensional road traffic and the like in an urban area, and is often used in urban railways and bullet trains. Viaduct E, as shown in FIGS. 1 and 2, the floor plate E ₁ which forms a floor viaduct E, piers supporting the deck E ₁ (peers) are composed of such as E _2, deck lower surface (Slab slab back) The noise reduction structure 1 is supported on the E ₃ side, and the slab slab R ₄ of the track R ₁ is supported on the floor slab upper surface (floor slab surface) E ₄ side. The viaduct E is, for example, a concrete bridge (concrete viaduct) whose main material is concrete.

The noise reduction structure 1 is a structure that reduces noise generated from the floor slab lower surface E ₃ of the viaduct E. The noise reduction structure 1 has a vibration suppression function that attenuates the vibration of the floor slab E ₁ and reduces structure noise radiated to the outside from the floor slab lower surface E ₃ . As shown in FIGS. 1 and 2, the noise reduction structure 1 includes a vibration damping layer 2, a constraining layer 3, a bonding layer 4, fixing members 5 and 6, and the like.

The damping layer 2 is a layer that attenuates vibration of the floor slab lower surface E ₃ of the viaduct E. Damping layer 2 has a function to reduce attenuates the vibration of the floor plate E _1, attenuates the vibrational energy of the floor plate E ₁ to reduce the amplitude of vibration of the deck E _1. Damping layer 2, as shown in FIG. 1, is approximately equal to the length between piers E _2, are substantially identical to the width of the slab E ₁ as shown in FIG. 2, the floor plate E ₁ It is formed with a thickness and weight sufficient to damp vibrations. The damping layer 2 is in close contact with the floor slab lower surface E _3, and the upper surface of the damping layer 2 is formed flat so as to be in close contact with the floor slab lower surface E _3. Is formed. The damping layer 2 is formed of, for example, a soft viscoelastic material having a rigidity lower than that of the constraining layer 3.

A soft viscoelastic material is an elastic material that is relatively softer than a rigid body.For example, the Young's modulus is about 1.0 to 1.0 × 10 ³ MPa at room temperature, preferably the Young's modulus is about 10 to 100 MPa, and the viscosity is desirably Combined, loss factor is 0.05 or more, thickness is 1mm or more. The soft viscoelastic material is formed of a flexible elastic material that does not have a sound absorbing function or a flexible viscoelastic material that does not have a sound absorbing function. Examples of such soft viscoelastic materials include natural rubber, styrene butadiene rubber, butyl rubber, ethylene propylene rubber (EPDM), chloroprene rubber, fluorine rubber, silicone rubber, urethane rubber, nitrile rubber, polynorbornene rubber, and acrylic rubber. Vulcanized rubber, styrene, olefin rubber, vinyl chloride TPE (thermoplastic elastomer), polystyrene, polyethylene, polypropylene, vinyl chloride, ethylene vinyl acetate copolymer (EVA) resin, Examples thereof include resins such as polyurethane, acrylic-butadiene-styrene copolymer (ABS), acrylic, and polycarbonate.

The constraining layer 3 is a layer that constrains the damping layer 2. The constraining layer 3 has a function of pressing the upper surface of the damping layer 2 against the floor slab lower surface E ₃ to suppress the damping layer 2 and improving the damping performance of the damping layer 2. As shown in FIGS. 1 and 2, the constraining layer 3 is formed with substantially the same length and width as the damping layer 2 and has a Young's modulus of 3.0 × 10 ³ MPa or more, for example. The constraining layer 3 is formed of, for example, a hard elastic material having higher rigidity than the vibration damping layer 2.

  Such hard elastic materials include general structural rolling (SS material), galvanized steel plates, metal steel plates such as aluminum and stainless steel, thermosetting resins such as epoxy and phenol, heat such as nylon and high density polyethylene. Inorganic materials such as plastic resin, ceramics, and mortar.

The constraining layer 3 absorbs noise from the sound source below the viaduct E toward the floor slab lower surface E ₃ when a hard elastic material having a sound absorbing function is used. For example, as shown in FIGS. 1 and 2, the constraining layer 3 absorbs and reduces noise generated from a vehicle V ₂ traveling under the viaduct E. Examples of such hard elastic materials include ceramics, inorganic particle binders obtained by bonding inorganic small particles with epoxy resin, foamed concrete, foamed resins such as polyurethane, epoxy, phenol, and gypsum board.

  The bonding layer 4 is a layer that bonds the damping layer 2 and the constraining layer 3 together. The bonding layer 4 is, for example, an epoxy type, urethane type, cyanoacrylate type, urethane resin type reaction type, vinyl acetate type or acrylic type emulsion type, chloroprene type or silicone type synthetic rubber type, ethylene vinyl acetate, etc. It is formed by a hot melt type adhesive such as copolymerization (EVA) or an adhesive. When the constraining layer 3 is a metal, the bonding layer 4 can be integrally formed with the soft viscoelastic material of the damping layer 2 by vulcanization adhesion or the like.

The fixing members 5 and 6 are members that fix the vibration damping layer 2 and the constraining layer 3. The fixing member 5 is an anchor material or the like that suspends the damping layer 2 and the constraining layer 3 and fixes the damping layer 2 and the constraining layer 3 to the floor slab E ₁ , and supports the damping layer 2 and the constraining layer 3 so as to press against the floor slab lower surface E _3. . As shown in FIGS. 1 and 2, the fixing member 5 is attached at a predetermined interval. The fixing member 6 is an angle member or the like that fixes the damping layer 2 and the constraining layer 3 to the pier E ₂ . As shown in FIG. 1, both ends of the fixing member 6 are fixed to the bridge pier E ₂ by an anchor material or the like.

Next, the operation of the viaduct noise reduction structure according to the first embodiment of the present invention will be described.
For example, when the hard elastic material equivalent to the constraining layer 3 is not laminated with the damping layer 2 and is directly attached to the floor slab E ₁ of the viaduct E as a vibrating body, the vibration damping performance of the damping layer 2 is not present. Therefore, the vibration of the floor slab E ₁ is directly transmitted to the hard elastic material, and the hard elastic material also vibrates greatly. For this reason, a considerable solid sound is also radiated from the hard elastic layer. On the other hand, as shown in FIGS. 1 and 2, in the first embodiment, the constraining layer 3 is joined to the floor slab lower surface E ₃ via the damping layer 2, and the damping layer 2 Since the upper surface is in close contact with the floor slab lower surface E ₃ , the damping layer 2 presses the floor slab lower surface E ₃ and attenuates the vibration energy of the floor slab E ₁ . At this time, the soft viscoelastic material of the damping layer 2 undergoes shear deformation along with the vibration of the floor slab E ₁ , but part of the vibration energy is converted into thermal energy due to internal loss due to the viscous resistance of the soft viscoelastic material. The vibration of the floor slab lower surface E ₃ is attenuated. Further, since the constraining layer 3 is laminated on the damping layer 2, deformation of the damping layer 2 is constrained by the constraining layer 3. For this reason, the shear deformation of the damping layer 2 is amplified, the internal loss of the damping layer 2 is amplified, and the vibration damping ability of the damping layer 2 is greatly enhanced. Further, not only the vibration damping capacity by the low damping layer 2 rigid laminated with constraining layer 3, the spring as a physical system to deck underside E ₃ viaduct E - dashpot - mass structure is formed also vibrate Blocked. For this reason, vibration is not transmitted to the constraining layer 3, and the vibration of the constraining layer 3 becomes very small. As a result, the solid sound radiated from the constraining layer 3 is also reduced.

The noise reduction structure of a viaduct according to the first embodiment of the present invention has the following effects.
(1) In the first embodiment, the damping layer 2 attenuates the vibration of the floor slab lower surface E ₃ of the viaduct E, and the restraining layer 3 restrains the damping layer 2. For this reason, when the damping layer 2 is adhered and adhered to the floor slab lower surface E ₃ of the viaduct E as a vibrating body, the damping layer 2 undergoes shear deformation during vibration and vibration energy is generated by the viscous resistance of the damping layer 2. Is converted into thermal energy, and the vibration of the floor slab E ₁ can be damped.

(2) In the first embodiment, the damping layer 2 is a soft viscoelastic layer having a lower rigidity than the constraining layer 3, and the constraining layer 3 is a hard elastic layer having a higher rigidity than the damping layer 2. For this reason, by constraining the damping layer 2 on the lower surface of the damping layer 2 and having the rigidity significantly higher than that of the damping layer 2 and restraining the damping layer 2 by the restraining layer 3, shear deformation of the damping layer 2 is achieved. The vibration damping performance of the damping layer 2 can be amplified. In addition, the surface on the sound receiving point side along the line is the constraining layer 3, but the constraining layer 3 is fixed to the floor slab E ₁ of the viaduct E via the damping layer 2, and the vibration blocking effect of the damping layer 2 is Thus, the vibration of the constraining layer 3 becomes very small. As a result, the solid sound radiated from the constraining layer 3 can be reduced.

(3) In the first embodiment, absorb the constraining layer 3 noise directed from below the sound source viaduct E to deck underside E ₃ of the viaduct E. Therefore, it is possible to reduce the noise radiated to the outside from the lower surface of the constraining layer 3 absorbs the noise emitted toward the lower side of the viaduct E to deck lower surface E ₃ by constraining layer 3 reduces the noise can do.

(Second Embodiment)
FIG. 3 is a cross-sectional view schematically showing a viaduct provided with a noise reduction structure of the viaduct according to the second embodiment of the present invention. 4 is a cross-sectional view showing a state cut along line IV-IV in FIG. In the following, the same parts as those shown in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.
The noise reduction structure 1 shown in FIGS. 3 and 4 has a soundproofing function for reducing noise transmitted from the floor slab E ₁ and reduces structure noise radiated to the outside from the floor slab lower surface E ₃ . The noise reduction structure 1 includes a constraining layer 3, a bonding layer 4, fixing members 5 and 6, a soundproof layer 7, and the like. The constraining layer 3 is a layer that constrains the soundproof layer 7 and has a function of improving the soundproof performance of the soundproof layer 7. The constraining layer 3 is a hard elastic layer that is in close contact with the lower surface of the soundproof layer 7 and is formed of a hard elastic material having higher rigidity than the soundproof layer 7. The bonding layer 4 is a layer that bonds the constraining layer 3 and the soundproof layer 7, and the fixing members 5 and 6 are members that fix the constraining layer 3 and the soundproof layer 7.

The soundproof layer 7 is a layer that reduces (absorbs) vibration transmission from the floor slab lower surface E ₃ of the viaduct E. The soundproof layer 7 has a function of making it difficult for noise transmitted from the floor slab lower surface E ₃ to be transmitted to the constraining layer 3, absorbing this noise in the propagation path, and confining this noise. Acoustical layer 7, as shown in FIG. 3, are substantially identical to the length between piers E _2, are substantially identical to the width of the slab E ₁ as shown in FIG. 4, the floor plate E ₁ It is formed with a thickness and weight sufficient to reduce noise. The soundproof layer 7 is in close contact with the floor slab lower surface E ₃ , the upper surface of the soundproof layer 7 is formed flat so as to be in close contact with the floor slab lower surface E _3, and the lower surface of the soundproof layer 7 is also formed flat. . The soundproof layer 7 is formed of, for example, a soft viscoelastic material having a rigidity lower than that of the constraining layer 3.

Such a soft viscoelastic material is an elastic material that is relatively softer than a rigid body, and is a material that is softer than the soft viscoelastic material of the vibration damping layer 2 shown in FIGS. 1 and 2. As such a soft viscoelastic material, for example, the Young's modulus is 1.0 × 10 ² MPa or less at room temperature, preferably the Young's modulus is 10 MPa or less, and the thickness is 3 mm or more, preferably 10 mm or more. Soft viscoelastic materials include, for example, vulcanized rubber foam rubber such as ethylene propylene rubber (EPDM), chloroprene rubber, urethane rubber, non-vulcanized rubber such as butyl rubber, gel such as silicone, vinyl acetate, EVA Viscoelastic materials such as emulsions such as acrylic resin and rubber latex are preferred.

Next, the action of the viaduct noise reduction structure according to the second embodiment of the present invention will be described.
As shown in FIGS. 3 and 4, when the vehicle V ₁ travels on the viaduct E, the vibration of the entire viaduct E is excited. In particular, the structure noise due to the vibration of the floor slab lower surface E ₃ greatly contributes to the noise along the railway. The noise reduction structure 1 shown in FIGS. 3 and 4 has a soundproof layer 2 having a low rigidity and a restraint having a rigidity much higher than that of the soundproof layer 2 at the lower part (track R ₂ side) of the floor slab lower surface E ₃ of the viaduct E. In this structure, the layer 3 is laminated. For this reason, when a spring-mass structure is formed as a physical system on the floor slab lower surface E ₃ of the viaduct E, and the rigidity of the soundproof layer 4 as a spring element is considerably small, the vibration transmissibility of the system becomes small, and the mass The vibration transmitted to the constraining layer 3 as an element is greatly reduced. As a result, the vibration amplitude of the soundproof layer 4 is reduced, and the solid sound generated from the soundproof layer 4 is reduced. In this way, since the soundproof layer 2 absorbs vibration transmission and suppresses the vibration of the constraining layer 3, the solid sound from the constraining layer 3 is reduced, and the structure noise transmitted from the viaduct E to the line is significantly reduced. .

The viaduct noise reduction structure according to the second embodiment of the present invention has the following effects.
(1) In this second embodiment, the soundproof layer 7 reduces the transmission of vibration from the floor slab lower surface E ₃ of the viaduct E, and the soundproof layer 7 is restrained by the constraining layer 3. For this reason, the soundproof layer 2 and the constraining layer 3 can be laminated on the lower surface (the track R ₂ side) of the floor slab lower surface E ₃ of the viaduct E that is a vibrating body to form a spring-mass structure. As a result, the vibration is absorbed by the sound-insulating layer 2 that is a low spring element and has low rigidity, and the vibration amplitude of the constraining layer 3 that is the surface layer on the track R ₂ side is reduced, and the radiation sound from the constraining layer 3 is reduced. Can be made.

(2) In the second embodiment, the soundproof layer 7 is a soft viscoelastic layer having a rigidity lower than that of the constraining layer 3, and the constraining layer 3 is a hard elastic layer having a rigidity higher than that of the soundproof layer 7. Therefore, the slab bottom surface E ₃ viaduct E, by adhering the acoustical layer 7 made of a soft viscoelastic material constant thickness to absorb the irregularities of the slab bottom surface E ₃ viaduct E (uneven surface) The soundproofing effect can be improved.

(Third embodiment)
FIG. 5 is a cross-sectional view schematically showing a viaduct provided with a noise reduction structure for the viaduct according to a third embodiment of the present invention. 6 is a cross-sectional view showing a state cut along line VI-VI in FIG.
5 and the noise reduction structure 1 shown in FIG. 6, has a damping function of attenuating the vibration of the floor plate E _1, and a soundproof function of reducing the noise transmitted from the slab E _1, the slab bottom surface E ₃ Reduce structure noise radiated to the outside. The noise reduction structure 1 includes a vibration damping layer 2, a constraining layer 3, a bonding layer 4, fixing members 5 and 6, a soundproof layer 7, and the like.

The vibration damping layer 2 is formed of a soft viscoelastic material having a lower elastic modulus than the soundproof layer 7. The constraining layer 3 is a hard elastic layer formed of a hard elastic material having higher rigidity than the vibration damping layer 2 and the soundproof layer 7. The joining layer 4 joins the damping layer 2 and the soundproofing layer 7 and joins the constraining layer 3 and the soundproofing layer 7, and the fixing members 5 and 6 attach the damping layer 2, the restraining layer 3 and the soundproofing layer 7. Fix it. The soundproof layer 7 is formed of a soft viscoelastic material that reduces transmission of vibration from the vibration damping layer 2 and has a lower elastic modulus than the vibration damping layer 2.

Next, the operation of the viaduct noise reduction structure according to the third embodiment of the present invention will be described.
As shown in FIGS. 5 and 6, when the vehicle V ₁ travels on the viaduct E and the viaduct E vibrates, structure noise tends to be radiated to the outside from the floor slab lower surface E ₃ . Since the damping layer 2 is stuck and stuck to the floor slab lower surface E ₃ , the damping layer 2 attenuates the vibration energy of the floor slab E ₁ . As a result, the vibration of the floor slab E ₁ is attenuated and the vibration of the lower surface of the damping layer 2 is reduced. Further, since the upper surface of the soundproof layer 7 is pressed against the lower surface of the damping layer 2 and is in close contact with the lower surface of the damping layer 2 through the bonding layer 4, noise transmitted from the damping layer 2 is transmitted along the propagation path. 7 is absorbed. Further, the upper surface of the constraining layer 3 is in close contact with the lower surface of the soundproof layer 7 via the bonding layer 4, and the constraining layer 3 constrains the soundproof layer 7. For this reason, the noise from the soundproof layer 7 is reduced, the amplitude of vibration on the lower surface of the constraining layer 3 is reduced, and the structure noise radiated to the outside from the lower surface of the constraining layer 3 is reduced.

The viaduct noise reduction structure according to the third embodiment of the present invention has the following effects.
In the third embodiment, the vibration damping layer 2 attenuates the vibration of the floor slab lower surface E ₃ of the viaduct E, the transmission of the vibration from the vibration damping layer 2 is reduced by the soundproof layer 7, and the soundproof layer 7 is restrained. Layer 3 is restrained. For this reason, the vibration energy of the floor slab E ₁ of the viaduct E is attenuated by the vibration damping layer 2, and the vibration transmitted from the vibration damping layer 2 to the constraining layer 3 is reduced by the soundproof layer 7. The structure noise radiated to the outside from the constraining layer 3 can be reduced.

(Fourth embodiment)
FIG. 7 is a cross-sectional view of a viaduct noise reduction structure according to a fourth embodiment of the present invention. 8 is a cross-sectional view showing a state cut along line VIII-VIII in FIG.
The noise reduction structure 1 shown in FIGS. 7 and 8 has a vibration damping function that attenuates the vibration of the floor slab E ₁ and a sound absorbing function that absorbs noise, and is radiated to the outside from the floor slab lower surface E _3. The noise of the lower part of the viaduct E is reduced while reducing the noise of objects. For example, as shown in FIGS. 7 and 8, the noise reduction structure 1 reduces the noise radiated to the outside from the floor slab lower surface E _{3 of the} viaduct E and also travels on a vehicle V traveling on a track R ₂ below the viaduct E. _2, and noise radiated toward the floor slab lower surface E ₃ of the viaduct E is reduced. The noise reduction structure 1 includes a damping layer 2, a constraining layer 3, a joining layer 4, fixing members 5 and 6, a sound absorbing layer 8, and the like. The joining layer 4 includes the damping layer 2 and the constraining layer 3. And the constraining layer 3 and the sound absorbing layer 8 are joined, and the fixing members 5 and 6 fix the vibration damping layer 2, the constraining layer 3 and the sound absorbing layer 8.

The sound absorbing layer 8 is a layer that absorbs noise from the sound source below the viaduct E toward the floor slab lower surface E ₃ . The sound absorbing layer 8 has a function of absorbing noise generated from the vehicle V ₂ traveling under the viaduct E. The sound absorbing layer 8 is substantially the same length as the length between the piers E ₂ and is substantially the same width as the width of the floor slab E ₁ . The sound absorbing layer 8 is in close contact with the lower surface of the constraining layer 3, and the upper surface of the sound absorbing layer 8 is flat so as to be in close contact with the lower surface of the constraining layer 3. The sound-absorbing layer 8 is made of, for example, glass wool, rock wool, aluminum or the like, fibers made of a resin such as polyethylene, ceramics, an inorganic particle binder obtained by binding small inorganic particles with an epoxy resin, foamed concrete, polypropylene, polyurethane, They are foamed resins such as epoxy and phenol, and gypsum board. The lower surface of the sound absorbing layer 8 is protected by, for example, an aluminum metal plate such as a punching metal having a large number of through holes.

The viaduct noise reduction structure according to the fourth embodiment of the present invention has the following effects in addition to the effects of the first embodiment.
In the fourth embodiment, the noise directed from below the sound source viaduct E to deck underside E ₃ of the viaduct E sound absorption layer 8 is absorbed. Therefore, noise radiated to the outside from the lower surface of the constraining layer 3 can be reduced, and noise radiated from the lower side of the viaduct E toward the floor slab lower surface E ₃ is absorbed by the sound absorbing layer 8 to reduce this noise. can do.

(Fifth embodiment)
FIG. 9 is a cross-sectional view of a viaduct noise reduction structure according to a fifth embodiment of the present invention. 10 is a cross-sectional view showing a state cut along line XX of FIG.
The noise reduction structure 1 shown in FIGS. 9 and 10 includes a constraining layer 3, a bonding layer 4, fixing members 5 and 6, a soundproof layer 7, a sound absorbing layer 8, and the like. The layer 3 and the soundproof layer 7 are bonded together, and the constraining layer 3 and the sound absorbing layer 8 are bonded together, and the fixing members 5 and 6 fix the constraining layer 3, the soundproofing layer 7 and the sound absorbing layer 8. In the fifth embodiment, in addition to the effects of the second embodiment, noise radiated from the lower side of the viaduct E toward the floor slab lower surface E ₃ can be absorbed by the sound absorbing layer 8 to reduce the noise.

(Sixth embodiment)
FIG. 11 is a cross-sectional view of a viaduct noise reduction structure according to a sixth embodiment of the present invention. 12 is a cross-sectional view showing a state cut along line XII-XII in FIG.
The noise reduction structure 1 shown in FIGS. 11 and 12 includes a vibration damping layer 2, a constraining layer 3, a bonding layer 4, fixing members 5 and 6, a soundproof layer 7, a sound absorbing layer 8, and the like. The joining layer 4 joins the constraining layer 3 and the soundproofing layer 7 and joins the constraining layer 3 and the sound absorbing layer 8, and the fixing members 5 and 6 are the vibration damping layer 2, the constraining layer 3, the soundproofing layer 7, and the sound absorbing layer. 8 is fixed. In the sixth embodiment, in addition to the effects of the third embodiment, noise radiated from the lower side of the viaduct E toward the floor slab lower surface E ₃ can be absorbed by the sound absorbing layer 8 to reduce the noise.

(Other embodiments)
The present invention is not limited to the embodiment described above, and various modifications or changes can be made as described below, and these are also within the scope of the present invention.
(1) In this embodiment, the case where the vehicles V ₁ and V ₂ are railway vehicles has been described as an example. However, the present invention can also be applied to other vehicles such as automobiles. Further, in this embodiment, the case where the viaduct E is a concrete viaduct has been described as an example. However, a steel bridge such as an iron girder bridge whose main material is steel, or a combination of a steel girder and a reinforced concrete slab is combined. The present invention can also be applied to viaducts such as girder bridges. Furthermore, in this embodiment, the vibration damping layer 2 or the soundproof layer 7 is fixed to the floor slab lower surface E ₃ by the fixing members 5 and 6, but the vibration damping layer 2 or the soundproof layer 7 is made of an adhesive or an adhesive. It can also be fixed to the floor slab lower surface E ₃ .

(2) In this embodiment, the case where the vibration suppression layer 2 has only the vibration suppression function and the soundproof layer 7 has only the soundproof function has been described as an example. The vibration layer 2 can be formed, or the soundproof layer 7 can be formed of a soft viscoelastic material having a vibration damping function. In this embodiment, the case where the constraining layer 3 and the soundproof layer 7 are joined by the joining layer 4 has been described as an example. However, the present invention is not limited to this case. For example, when the soundproof layer 7 is non-vulcanized butyl rubber, the bonding layer 4 can be omitted, and the constraining layer 3 and the soundproof layer 7 can be directly bonded using the adhesiveness of the non-vulcanized butyl rubber itself. . Further, when the soundproof layer 7 is a gel, emulsion, latex or the like, the bonding layer 4 can be omitted, and the constraining layer 3 and the soundproof layer 7 can be directly adhered using the property of curing reaction from the liquid state. Furthermore, in this embodiment, the case where the damping layer 2, the constraining layer 3, the soundproofing layer 7, the sound absorbing layer 8, and the like are laminated is described as an example, but these layers are arbitrarily combined to form a multistage structure. You can also For example, a plurality of constraining layers 3 and soundproofing layers 7 can be alternately stacked between the vibration damping layer 2 and the sound absorbing layer 8.

It is sectional drawing which shows roughly the viaduct provided with the noise reduction structure of the viaduct concerning 1st Embodiment of this invention. It is sectional drawing which shows the state cut | disconnected by the II-II line | wire of FIG. It is sectional drawing which shows roughly the viaduct provided with the noise reduction structure of the viaduct concerning 2nd Embodiment of this invention. It is sectional drawing which shows the state cut | disconnected by the IV-IV line of FIG. It is sectional drawing which shows roughly the viaduct provided with the noise reduction structure of the viaduct concerning 3rd Embodiment of this invention. It is sectional drawing which shows the state cut | disconnected by the VI-VI line of FIG. It is sectional drawing of the noise reduction structure of the viaduct concerning 4th Embodiment of this invention. It is sectional drawing which shows the state cut | disconnected by the VIII-VIII line of FIG. It is sectional drawing of the noise reduction structure of the viaduct concerning 5th Embodiment of this invention. It is sectional drawing which shows the state cut | disconnected by the XX line of FIG. It is sectional drawing of the noise reduction structure of the viaduct concerning 5th Embodiment of this invention. It is sectional drawing which shows the state cut | disconnected by the XII-XII line | wire of FIG.

Explanation of symbols

1 Noise reduction structure 2 the damping layer 3 constraining layer 4 bonding layer 5, 6 fixing member 7 soundproofing layer 8 backing layer V _1, V ₂ vehicle R _1, R ₂ track E viaduct E ₁ bed Version E ₂ piers E ₃ bed plate Bottom (bottom)

Claims (4)

A concrete viaduct noise reduction structure that reduces noise generated from a concrete viaduct,
A damping layer for attenuating vibration on the lower surface of the concrete viaduct;
A constraining layer for constraining the vibration damping layer,
The damping layer is formed of a vulcanized rubber of EPDM, which is a viscoelastic material having a lower rigidity and a Young's modulus of 10 to 100 MPa than the constraining layer, with the upper surface of the damping layer being in close contact with the lower surface of the concrete viaduct. And
The constraining layer is an elastic material having higher rigidity than the vibration damping layer, and is formed of an inorganic particle binding material in which inorganic small particles are bonded with an epoxy resin. Absorbing noise toward the bottom,
Noise reduction structure of concrete viaduct characterized by A concrete viaduct noise reduction structure that reduces noise generated from a concrete viaduct,
A damping layer for attenuating vibration on the lower surface of the concrete viaduct;
A soundproof layer that reduces transmission of vibration from the damping layer;
A constraining layer for constraining the soundproof layer,
The vibration damping layer is in close contact with the lower surface of the concrete viaduct, and is formed of a vulcanized rubber of EPDM, which is a viscoelastic material having a Young's modulus higher than that of the soundproof layer and having a Young's modulus of 10 to 100 MPa,
The soundproof layer is formed of a vulcanized rubber foam rubber of EPDM, which is a viscoelastic material having a lower modulus of elasticity than that of the vibration damping layer and a Young's modulus of 10 MPa or less,
The constraining layer is formed of a metal steel plate that is an elastic material having a rigidity higher than that of the vibration damping layer and the soundproof layer and having a Young's modulus of 3.0 × 10 ³ MPa or more,
Noise reduction structure of concrete viaduct characterized by In the noise reduction structure of the concrete viaduct according to claim 2 ,
A sound absorbing layer that adheres closely to the lower surface of the constraining layer and absorbs noise from the sound source below the concrete viaduct toward the lower surface of the viaduct;
Noise reduction structure of concrete viaduct characterized by A concrete viaduct noise reduction structure that reduces noise generated from a concrete viaduct,
A damping layer for attenuating vibration on the lower surface of the concrete viaduct;
A soundproof layer that reduces transmission of vibration from the damping layer;
A constraining layer for constraining the soundproof layer,
The vibration damping layer is in close contact with the lower surface of the concrete viaduct, and is formed of a vulcanized rubber of EPDM, which is a viscoelastic material having a higher elastic modulus and a Young's modulus of 10 to 100 MPa than the soundproof layer,
The soundproof layer is formed of a vulcanized rubber foam rubber of EPDM, which is a viscoelastic material having a lower modulus of elasticity than that of the vibration damping layer and a Young's modulus of 10 MPa or less,
The constraining layer is an elastic material having rigidity higher than that of the vibration damping layer and the soundproof layer, and is formed of an inorganic particle bonding material in which inorganic small particles are bonded with an epoxy resin, and from a sound source below the concrete viaduct Absorbing noise toward the lower surface of this constraining layer,
Noise reduction structure of concrete viaduct characterized by

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